Storage containers such as refrigerators and heating cabinets can store a material stored in a storage chamber thereof at a desired temperature different from a temperature of outside air such as a living temperature. For example, a refrigerator can maintain freshness of a stored material such as various foods for a long time. In addition, a heating cabinet can maintain a stored material such as various foods at a ready-to-eat temperature (for example, 80° C.) or the like.
A storage container is expected to improve performance of heat insulation between the inside and outside of the storage chamber. Generally, a wall portion separating the outside of the storage container and the inside of the storage chamber is composed of a heat-insulating material such as foamed urethane. A part of the wall portion may be composed of a second heat-insulating material of which thermal conductivity is lower than that of foamed urethane or the like, so as to improve the heat insulating performance of the storage container. As the second heat-insulating material, for example, a vacuum heat-insulating material disclosed in PTL 1 may be exemplified.
The vacuum heat-insulating material has, for example, a plate-shaped porous base material and an exterior body accommodating the base material, a pressure in the inside of the exterior body being reduced to a high vacuum. The exterior body has a structure in which films covering the front and back surfaces of the base material are welded or bonded to each other in the outside of an outer periphery of the base material. In the vacuum heat-insulating material, thermal conductivity inside thereof is extremely low by reducing a pressure in the inside thereof and, for example, the thermal conductivity is approximately 1/20 compared to the heat-insulating material such as foamed urethane.